Re: Dumping unexec

[Po Lu <luangruo@yahoo.com>]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

> IIUC, adding support for the pdumper to these systems should be fairly
> simple, consisting mostly of replacing calls to `mmap` with
> `malloc+read`.

Windows 9x's virtual memory facilities are adequate for the portable
dumper, but it crashes at runtime for reasons unknown with debugging a
vain endeavor.  DJGPP's fall short of what is required to implement
mprotect, under the memory extender they distribute, but there I've
never tried building the portable dump file loader already implemented
in pdumper.c.

> Has someone with access to such systems tried that?

Easier said than done: debugging Emacs on Windows 9x is a tedious
exercise that entails, among other tasks, transferring binaries between
the development machine and the target by way of an intermittent
connection to a Samba share, which is a hit or miss insofar as success
is concerned.  Not helping matters is the scarcity of time I can spend
with suitable target machines.

> Is there some more serious issue?

On my last attempt I failed to extract anything approaching an
intelligible backtrace from GDB.  However, none of these systems are to
receive support for the MPS, so why has it suddenly become an issue of
immediate importance that unexec be given the axe?